Conventional aluminium high pressure die casting utilizes a hydraulic cylinder to advance a shot tip, displacing molten aluminium from the shot sleeve into the die cavity, overcoming the resistance to flow through the restricted gate area. When the die cavity is filled with molten aluminium, the pressure applied to the hydraulic shot cylinder is transferred to the molten aluminium based upon the ratio of the shot cylinder and shot tip cross-sectional area. If the die cavity containing one end of a submerged member fills and becomes pressurized before the die cavity or region of the die containing the opposing end of the submerged member, a resultant force is imposed on the end of the submerged member. To avoid movement of the submerged member, a mechanism must be employed, such as a clamp or a friction or form fitting die, to resist the force. As the cross-sectional area of the member increases, the forces become very high and difficult to manage with such mechanisms. Subsequent to filling of the die cavity, the pressure applied to the hydraulic cylinder advancing the shot tip is typically increased (i.e., intensified) by, for example, a factor of two times to reduce the volume of entrapped air and increase the rate of heat transfer. Also, once the in-gates have frozen-off through solidifying, which usually occurs prior to the solidifying of the entire die cavity, even the increased pressure fails to reach the material within the cavities being molded.
U.S. Pat. No. 3,664,410 to Groteke and U.S. Pat. No. 4,779,666 to Ruhlandt et al., disclose each a die casting process and apparatus.